By now you have no doubt read that the big cabin, ultra-long-range Falcon 7X uses fly-by-wire technology to connect the human pilot to the flight controls, a first for business jets. Falcon insists on calling this a digital flight control system (DFCS) because all of the computers are digital, not analog, but to a pilot the intrigue is that there is no mechanical link between the cockpit controls and the surfaces that actually guide the flight path of the airplane.
So what is it like to fly the Falcon 7X? Not like any other business jet, that's for sure. And not exactly the same as any of the airline jets that use fly-by-wire technology because each airplane manufacturer has its own concepts of how an airplane should fly to best conduct its mission.
Dassault has been building extremely capable military fighters using DFCS for 25 years and it is that experience that most directly flows into the flying characteristics of the 7X. Obviously, a fighter has to be very maneuverable, and the 7X is, but less apparent in a modern fighter is the requirement for smooth and steady flight with minimum demands on the pilot. While jinking around in a dogfight is a necessary capability, the common mission of a fighter is to deliver weapons to ground targets or to shoot over the horizon at other aircraft. In both cases, a stable and steady pass is the best guarantee of success.
When it comes to the business jet mission a smooth and stable flight with the precision to make a safe and predictable touchdown in the worst weather is what everybody wants -- particularly the passengers. So in the 7X the computers at the heart of the DFCS keep the airplane on a steady flight path until the human pilots or autopilot asks for a change. The computers automatically correct for any gusts or turbulence that displace the 7X from its present flight path, which keeps the airplane traveling to where you want it to go, but also has the unintended effect of smoothing the ride. Because the DFCS system instantly makes very small control movements when the 7X hits turbulence, the bumps, wallows and rolls that other airplanes experience are minimized. That long and very flexible wing also helps damp out the jolts of turbulence that are transmitted to the cabin.
But back to what it's like to fly the 7X. The best way I can describe it is that you point and shoot. Put the 7X on the flight path you want to maintain, and it stays there until you make a new control input.
The sidestick is nice and beefy with a substantial grip and rather long travel in any direction. You move this stick rather than simply applying pressure with very little displacement as on some other sidesticks. There is a very positive centering spring so the stick returns to neutral as soon as you release pressure. The two sticks are not connected mechanically so only one moves at a time, but if both pilots make simultaneous inputs, the sticks shake to warn that only one can fly at a time. A priority select switch can give one pilot the ability to override the other's inputs.
The sensation of flying the 7X is immediately natural with the airplane responding smoothly, and exactly as I expected, to stick movement. However, once the airplane is heading where I want it to go, I notice the difference because I have always had to trim off the stick force in every other airplane. But not in the 7X. When the flight path indicator on the primary flight display (PFD) is on target, you simple release pressure and the stick centers and the 7X stays on that path. It only takes a couple of minutes to forget about trim, but after a lifetime of flying other airplanes, it comes initially as a pleasant surprise.
For example, on rotation for takeoff you are holding the same stick force against springs when the flight path reaches the target as you were when you started to bring the nose up. In any other airplane if you release back pressure the nose will drop, seeking its trim speed, so you have to hold the stick back until you can trim off the pressure. But the 7X is constantly trimming automatically to maintain a constant flight path.
One of the most impressive displays of the way the DFCS holds flight path is by making huge airspeed changes. In level flight, hands off, I pushed the power and airspeed up to 300 knots indicated and made no flight control inputs while the 7X held a steady flight path. I then brought the power back to flight idle, and as speed limits were reached, extended slats and flaps, again hands off, and the flight path remained constant. The attitude of the airplane changed enormously from nearly level to way nose up, but the DFCS held the flight path.
The 7X allows pilots to think about the mission in a new way. Instead of concentrating on how to make the airplane go where you want it to, you can focus on where you want it to go. The 7X completes the design logic loop and makes ultimate use and sense of the EASy glass cockpit, which displays flight path instead of attitude as primary. You see the flight path on the PFD, you see the flight path command, and you adjust the path to where you want it, and it stays there. Pilot workload is cut to a fraction of what it takes to fly a conventional airplane.
